Lampholders for electric discharge lamps



Dec. 6, 1966 J. M. PISTEY 3,29%638 LAMPHOLDERS FOR ELECTRIC DISCHARGE LAMPS Filed Oct. 1, 1963 2 Sheets-Sheet l INVENTOR Jaxfi n A7. lsey mt i"? Dec. 6, 1966 J. M. PISTEY 3,290,638

LAMPHOLDERS FOR ELECTRIC DISCHARGE LAMPS Filed 001:. l, 1963 2 SheetsSheet 2 INVENTOR. fa/217% H'slf'eg,

q VQ' W United States Patent 3,290,638 LAMPHOLDERS FOR ELECTRIC DISCHARGE LAMPS John M. Pistey, Fairfield, Coun., assignor to General Electric Qompauy, a corporation of New York Filed Oct. 1, 1963, Ser. No. 313,061 6 Claims. (Cl. 33956) This invention relates generally to lampholders for electric discharge lamps and more particularly to such improved lampholders for use in conjunction with fluorescentt lamps.

A fluorescent lamp of the single pin type is generally supported at one end by a lampholder having a retractable spring-biased plunger (high-voltage lampholder) and at the other end by a lampholder that provides a fixed support. Thus, the fluorescent lamp is resiliently held between the pair of lampholders. The lampholders also provide the means through which connections are made from the ballast to the lamp. To place the fluorescent lamp in the lampholders, the pin at one end of the lamp is first inserted in the lampholder with the spring-biased plunger, and the spring-biased plunger is compressed until the pin at the other end of the lamp can be engaged in the other lampholder.

In a commonly used lampholder construction the lamp pin is inserted into an aperture formed in the plunger and an axial pressure against the plunger causes the plunger to be retracted into the housing. The housing of such a lampholder is usually constructed of one molded base formed with a relatively deep cavity in which the plunger, spring and other parts are assembled. After the parts are assembled a cover which closes the cavity is attached.

A disadvantage of such a conventional arrangement is that because of the depth of the base the cure time required for the molded part is relatively longer than would be the case if the part molded were of shorter depth. Thus, to enhance the efiiciency of the molding operation it is particularly desirable in the manufacture of molded parts that they be of relatively shallow depth and simple configuration. By reducing the depth of the molded part, it will be appreciated that it is possible to thereby reduce the cost of the molding operation since more cavities may be used per mold and shorter curing times may be employed. Another disadvantage in using a single molded housing construction with a relatively deep cavity is that the assembly procedures are complicated for assembling the parts in the deep cavity. It will be apparent that it is generally easier to assemble parts in a relatively shallow cavity.

The electrical contact with the pin of the fluorescent lamp in the high-voltage lampholder is usually provided by a contact means, such as a washer, which engages one end of the plunger spring. The plunger spring serves as a current carrying member of the electrical circuit, and the other end of the spring is in electricalcontact with a contact strip to which the leads from the ballast are connected. Once the lamp is in the lampholders sufficient axial force must be exerted by the plunger spring to establish a good electrical contact between the lamp pin and contact strip. Also, the plunger should have sufficient travel to reliably handle lamps within the range of tolerances for the lamp and for mounting the lampholders. The manufacturing tolerances for a typical fluorescent lamp are plus or minus of an inch and the mounting tolerances of the lampholders are plus or minus of an inch. In view of the lamp and lampholder mounting tolerances it is particularly desirable that the plunger be allowed to retract into the housing as far as possible.

3,290,638 Patented Dec. 6, 1966 ice A general object of this invention is to provide an improved lampholder for electric discharge lamps such as fluorescent lamps.

Another object of the invention is to provide an improved lampholder utilizing molded parts of relatively shallow depth.

It is still a further object of the present invention to provide an improved lampholder having an improved spring-biased plunger arrangement providing maximum travel for a given axial width of the lampholder.

A more specific object of the present invention is to provide an improved lampholder construction using parts that can be more efficiently molded.

Another specific object of the present invention is to provide a lampholder having an imporved contact-strip arrangement for use in conjunction with a spring-biased plunger.

In accordance with one form of the invention, I have provided an improved lampholder for a fluorescent lamp with a split insulating housing arrangement. The insulating-housing arrangement includes a first and a second housing section which provide a front and a rear vertical wall and which are joined to form side walls disposed in perpendicular relationship to the vertical walls. One of the housing sections is formed with a projection that extends into the other housing section to provide a guide wall for the conductor receiving aperture formed in the other housing section. The projection also engages a resilient contact strip disposed in edgewise relation along the vertical wall of the other housing section to hold the strip therein. At one end the resilient contact strip is formed with an angulated pressure lock portion that is disposed at the inner side of the conductor receiving aperture for engaging a conductor in locking relation. At the other end the resilient contact strip includes a portion for connection in electrical circuit with the fluorescent lamp.

According to another aspect of the invention, the housing sections are formed with a plunger-receiving opening with a pair of opposed axially extending ribs formed thereon. A plunger having axially extending slots engaging the ribs in the opening is slideably mounted in the opening. A current-carrying spring member normally biases the plunger outwardly of the housing. Preferably, a spring centering means is formed on the vertical wall of one of the housing sections, and the contact strip includes an ear spaced from the centering means and engaging the spring member. Further, the contact strip includes a transversely extending element disposed under the end of the spring member to provide electrical contact therewith.

With the split-housing arrangement it was possible to reduce the cost of the molded parts and to simplify the assembly of the other components in the molded parts because of the relatively shallow depth and configuration of the molded parts. Further, for a given axial width of a high-voltage lampholder, it was possible to provide an increase in the travel of the lampholder plunger.

Further aspects of my invention will become apparent upon consideration of the following more detailed description. The subject matter which I regard as my invention is set forth in the appended claims. The invention, however, together with further objects and advantages thereof may be best understood by referring to the following description taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a side elevational view showing a general arrangement of a fluorescent lamp supported between a pair of lampholders embodying one form of the invention;

FIGURE 2 is an enlarged front elevational view of the high-voltage lampholder shown at the right end of the 3 lamp in FIGURE 1 with the plunger in the extended position( lamp disengaged);

FIGURE 3 is a sectional view taken generally along the line 33 of FIGURE 2;

FIGURE 4 is a view in perspective of the plunger and a fragmentary portion of a housing section of the lampholder illustrated in FIGURES 2 and 3 illustrating the cooperative relationship between the housing section .and the plunger;

FIGURE 5 is a rear elevational view of the front housing section of the high-voltage lampholder shown in FIGURE 1;

FIGURE 6 is an enlarged front elevational view of the rear housing section of the high-voltage lampholder shown in FIGURE 1 with the spring positioned on the centering means;

FIGURE 7 is an enlarged perspective view of the contact strip shown in FIGURE 6;

FIGURE 8 is a top view of the high-voltage lampholder shown in FIGURE 1;

FIGURE 9 is a front elevational view of the lowvoltage lampholder shown at the left end of the arrangement shown in FIGURE 1;

FIGURE 10 is an enlarged sectional view taken generally along the line 10-10 of FIGURE 9;

FIGURE 11 is an enlarged front elevational view of the rear housing section of the low-voltage larnpholder shown in FIGURE 9;

FIGURE 12 is an enlarged rear view of the front housing section of the lampholder shown in FIGURE 9 with the front housing section removed;

FIGURE 13 is an enlarged view of the contact strip shown in FIGURE 12; and

FIGURE 14 is a sectional view taken substantially on the plane of line 14-14 of FIGURE 2.

Having more specific reference now to FIGURE 1 of the drawings, I have illustrated therein a fluorescent lamp 10 of the single-pin type supported at the right end by a a high-voltage lampholder 11 and at the left end by a low-voltage lampholder 12. The lampholders 11, 12 in which the invention is embodied, are supported from a plate 13. The plate 13 may form the part of a lighting fixture or other surface on which it is desired to attach the lampholders 11, 12. The fluorescent lamp 10 which is supported by lampholders 11 and 12 includes a tubular glass enevelope 14 with a pair of bases 15 and 16, each of which have a single pin (not shown) extending therefrom.

It will be apparent from the general arrangement shown in FIGURE 1 that for a given lamp length, the lampholders 11 and 12 must be mounted and attached to the supporting plate 13 in a predetermined spaced relation. With the lampholders 11, 12 so mounted, the lamp 10 is inserted into the lampholders by first depressing a springbiased plunger 17 into the lampholder 11 sufiiciently so that the pin at the left end of the lamp 10 can be inserted in the aperture provided inlampholder 12. To insert the lamp 10, it is held at an angle to the center line joining the two lampholders 11, 12 and is forced towards the lampholder 11 to push the plunger 17 inwardly. When the pin at the left end of the lamp 10 is engaged in lampholder 12, the lamp 10 is resiliently supported between the two lampholders 11 and 12.

Having more particular reference now to the FIGURES 2 to 7, I will now more particularly describe the construction of the high-voltage larnpholder 11, which is shown at the right end of the lamp-mounting arrangement illustrated in FIGURE 1. It will be noted that a split housing arrangement is provided and is comprised of two molded housing sections 18 and 19. For convenient reference, the section 18 which is adjacent to the lamp 10 will hereinafter be referred to as the front housing section and the section 19 joined therewith shall be referred to as the rear section. The front and rear housing sections 18, 19 are joined to form a unitary housing structure by a suitable securing means such as an eyelet or rivet 20. The plunger 17 is slidably mounted within plunger-receiving openings 21, 22 in the front and rear housing sections 18, 19. The front and rear housing sections 18, 19 and the plunger 17 are preferably formed from any moldable electrically insulating material such as urea.

As is best seen in the exploded view of FIGURE 4 the plunger 17 is cylindrical in shape and includes a flange 23 which engages an annular stop shoulder 24 formed in the front housing section 18 when it is in the extended position. Also the plunger 17 includes a pair of opposed grooves or slots 25, 26 which engage the opposed axially extending ribs 27, 28 formed in the plunger receiving opening 21. When the plunger 17 is in the outwardly extended position as shown in FIGURE 3, it will be seen that the flange 23 is in contact with the annular stop shoulder 24 formed in the front housing section 18 and any further outward axial movement of the plunger 17 is thereby restrained. The plunger 17 is formed with a pin-receiving aperture 30 and a relatively larger opening 31 for receiving a current-carrying spring 32.

The spring 32, as shown in FIGURE 3, is centered at one end by a centering means which is comprised of a ribbed boss 33 formed on the vertical wall 34 of the rear housing section 19. At the other end the spring 32 engages a contact washer 35 which provides an electrical connection between the lamp pin and the spring 32. The spring 32 may be formed from any suitable resilient and electrically conductive material, and in the fully extended position is designed to exert a spring force to maintain the plunger 17 in the extended position.

As is best seen in FIGURE 5, the front housing section 18 is formed with a foot or projection 37 which extends outwardly of the front housing section 18. The projection 37 includes three rib portions 38, 39 and 40 and engages the rear housing section 19 in interlocking relation to provide structural rigidity between the housing sections 18 and 19. It was found that with the projection 37 extending into the rear housing section 19, as shown in FIGURES 3 and 8, the split housing arrangement had the requisite mechanical strength and permitted the use of molded housing sections 18, 19 having a relatively shallow depth. This results in the important advantage that more cavities per mold and shorter cure times are possible, as compared to a lampholder arrangement utilizing a non-split housing arrangement. Also, the projection 37 provides for an accurate fit between the two housing sections 18 and 19.

Referring to FIGURES 5 and 8, the end surface of the rib portion 38 provides a guide wall 41 for the conductor receiving aperture 42 and serves to guide a conductor or lead into proper pressure-lock engagement. The end surface of portion 39 locks the contact strip in the rear housing section 19 and also provides a wall 43 for the tool-receiving aperture 44. Referring to FIGURE 3, it will be observed that the contact strip 45 is illustrated in phantom lines in its operative position in edgewise relation between the vertical wall 34 of rear housing section 19 and the end surface of projection portion 39. This relationship is even more clearly illustrated in FIGURE 14, wherein the contact strip 45 may be seen to be in place between wall 34 and projection portion 39. It will also be seen in FIGURE 14 that the projection portion 38 provides the guide wall 41 for the conductor receiving aperture 42 as well as engaging a portion of the contact strip 45.

As is seen in FIGURES 6 and 7, the resilient contact strip 45 includes an angulated pressure-lock portion 46 and spring contact portion 47. The pressure-lock portion 46 is disposed in the cavity 9 formed in the rear housing section 19 with an interference fit so that the contact strip 45 can be held in position within the rear housing section 19 during assembly. Further, it will be seen that the pressure lock portion 46 is disposed so that the end is located at the inner side of the conductor-receiving aperture 42.

The end of pressure lock portion 46 is formed with an indentation 49 for facilitating the entry of the conductor into pressure-lock engagement.

The spring contact portion 47 of the contact strip 45 includes tapered ear 50 which, as shown in FIGURE 6, serves to position and lock the spring 32 against the boss 33, and also includes a transversely extending contact portion 51 which extends in a direction parallel to the vertical wall 34 of the rear housing section 19. The contact strip 45 may be formed from any suitable electrical conducting material, preferably Phosphor bronze, which may be readily formed to the configuration described herein. It will be noted that the contact strip 45 is disposed in edgewise relation with respect to the wall 34 and that the transverse contact portion 51 is situated between a pad 52 formed on the wall 51 and the end of the spring 32 whereby the spring 32 always presses against the transverse contact portion 51 irrespective of the position of the plunger 17 When the spring 32 is inserted over the centering means or element 33 on the wall 34, the spring 32 effects a slight outward displacement of the spring contact portion 47. The ear 50 is held resiliently against the spring 32. This provides the advantage that a spring type of engagement is provided between the ear 50 and the spring 32 which permits the spring 32 to be held in position during assembly. H V

. In assembling the high-voltage lampholder 11, the contact strip 45 is initially placed in the cavity 9 of the rear housing section 19 and the spring 32 is clipped in position between the centering element 33 and the tapered ear 50, as shown in FIGURE 6. The plunger 17 is assembled in the plunger receiving opening 21 of the front housing section 18, and the contact washer 35, which provide the electrical contact with the lamp, is inserted into the spring-receiving opening 31 of the plunger 17. The front and rear housing sections 18, 19 are then joined by setting the eyelet 20.

Having reference to FIGURES 9 through 13, I will now more particularly describe the low-voltagelampholder 12 used at the left end of the fluorescent lamp support arrangement shown in FIGURE 1. It will be seen that the low-voltage lampholder 12 also utilizes a split housing arrangement and includes a front housing section 55, a rear housing section 56, a pair of contact strips 57, 58 and an eyelet 59. The rear housing section 56, as shown in FIGURE 11 is formed with a first projection 60 and a second projection 61 which extend outwardly for interlocking engagement with the front housing section 55. The first projection 60 including a pair of rib portions 62, 63 provides a guide wall for the conductor-receiving aperture 64, 65, and the first projection 60 also locks the upper end of the contact strips 57, 58 in the cavities 66, 67 formed in the front housing section 55. The second projection 61 extends into front housing section 55 to lock the lower end of the contact strips 58, 59 in position. Both projections 60, 61 provide a stronger and more rigid unitary structure when housing sections 55, 56 are joined together because of the interlocking effect of the projections 60, 61. Also, the projections 60, 61 facilitate the assembly of the parts.

The contact strips 57, 58 used in this illustrated embodiment of the invention were essentially symmetrical. Accordingly, I have used the same reference numbers to identify the corresponding portions thereof, the portions of contact strip 58 being identified by primed numerals to distinguish them from the contact strip 57. As is best seen in FIGURE 13, the contact strip 57 includes a pin contact portion 70 and an angulated pressure lock portion 71. The pressure lock portion 71 includes an indentation 72 to facilitate entry of the conductor lead into pressure locking engagement. It will be noted that the contact strips 57, 58 are disposed in edgewise relation along the vertical wall 74 and the pin contact portions 70, 70 confront the lamp pin receiving aperture 75, so that when the lamp pin is inserted through the opening 75 the pin is resiliently engaged between the pin contact portions 70, 70'. Further, it will be noted that the rib 76 formed in the front housing section provides the proper spacing for the pin contact portion 7 0, 70.

It will be appreciated that although in the illustrated embodiments of the invention I have shown a pressure lock type of contact terminal for connection to the conductors, other types of terminal arrangements can be used.

The assembly of the low-voltage lampholder involves combining five parts. The pressure lock portions 70, of the contact strips 57, 58 are snapped into position in the cavities 66, 67 in the front housing section 55. The rear housing section 56 is then joined with the front housing section 55 by setting the eyelet 59 to complete the assembly.

From the foregoing description it will be apparent that I have provided improved lampholder construction utilizing a split housing arrangement formed of two molded housing sections of relatively shallow depth. An important advantage of such an arrangement is that the mold times required to form these parts has been reduced as compared with comparable lampholders of the prior art employing a single molded part for the insulating housing. Further, the split housing arrangement has made it possible to use simplified mold designs and thereby increase efficiency of the molding operation. Also, an improved spring-biased plunger arrangement has been provided. Further, the interlocking projections utilized in the improved split housing construction not only provide structural rigidity for the insulating housing when assembled on a fixture but also facilitate proper fitting and assembly of the parts during manufacture.

While I have described herein exemplifications of the invention as applied to fluorescent lamps of the single pin type, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the invention. For example, the lampholders can be readily adapted to bi-pin type of fluorescent lamps and other terminal lead arrangements may be employed in conjunction with the improved arrangement. It is therefore intended in the following claims to cover all such equivalent variations as come within the true spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A lampholder for an electric lamp comprising a split housing formed of a front and a rear housing section of molded insulating material, each of said housing sections having a vertical wall, said front housing section having a ribbed projection on the vertical wall thereof extending into said rear housing section, an elongated resilient contact strip disposed in edgewise relation along the vertical wall of said rear housing section, said projection on said front housing having means for locking said resilient contact strip in said rear housing section, means for connecting one end of said resilient contact strip with a lead wire, said front and rear housing sections having a plunger-receiving opening formed therein, said opening in at least one of said housing sections having a pair of opposed axially extending ribs formed thereon, a plunger slidably mounted in said plunger-receiving opening, said plunger having opposed slots formed therein and engaging said ribs formed in said plunger-receiving opening, a currentcarrying spring member engaging said plunger for normally biasing said plunger outwardly from said housing, means on said plunger engageable with said front housing section for limiting the outward movement of said plunger, said contact strip including a spring contact portion engaging one end of said current-carrying spring member to provide an electrical contact therewith, and means at the other end of said spring member for providing an electrical connection with the lamp.

2. The lampholder set forth in claim 1 wherein said rear housing section includes a spring centering means formed on the vertical wall of said rear housing section to center the end of said spring member which is in electrical contact with said spring contact portion of the contact strip, said spring contact portion including an ear spaced from said centering means and engaging said spring member to lock said spring member in position, and said spring contact portion also including a transversely extending elernent disposed under the end of the spring member to provide an electrical contact therewith.

3. In a lampholder for an electric lamp an improvement comprising a split housing formed of insulating material with front and rear vertical walls in perpendicular relationship to side walls, said split housing including a first housing section and a second housing section joined to form said side walls of said split housing, one of said housing sections having a projection divided into at least two portions and extending into the other housing section, said other housing section having at least one conductorreceiving aperture formed therein and one of said projection portions forming a guide wall for said conductorreceiving aperture, and at least one resilient contact strip disposed in edgewise relation between the vertical wall of said other housing section and the other of said projection portions, said other projection portion thereby locking said resilient contact strip in said other housing section, said resilient contact strip having an angulated pressure lock portion at one end thereof disposed at the inner side of said conductor receiving aperture for engaging a conductor in pressure-locking relation and said resilient contact strip having a spring contact portion at the other end thereof for connection in electrical circuit with the electric lamp.

4. In a lampholder for an electric lamp an improvement comprising a split housing formed of insulating material with front and rear vertical walls in perpendicular relationship to side walls, said split housing including a first housing section and a second housing section joined to form said side walls of said split housing, one of said housing sections having a projection extending into the other housing section, said other housing section having at least one conductor receiving aperture formed therein and said projection forming a guide wall for said conductor receiving aperture, and at least one resilient contact strip disposed in edgewise relation along the vertical wall of said other housing section and having one edge adjacent to the vertical wall of said other housing section and the other edge adjacent to said projection, said projection locking said resilient contact strip in said other housing section, said resilient contact strip having an angulated pressure lock portion at one end thereof disposed at the inner side of said conductor receiving aperture for engaging a conductor in pressure locking relation and said resilient cont-act strip having a spring contact portion at the other end thereof for connection in electrical circuit with the electric lamp, at least one of said housing sections being formed with a plunger-receiving opening, a plunger slidably mounted in said plunger receiving opening, a current carrying coil spring having one end engaging said plunger to bias said plunger outwardly from the housing and the other end engaged against the rear vertical wall, said other housing section formed with a spring centering means on the vertical wall thereof and positioning said coil spring in perpendicular relationship to said last mentioned vertical wall and said spring contact portion of the contgct strip comprised of a transversely extending element disposed between one end of said current-carrying coil spring and the vertical wall of said other housing section, and a tapered ear spaced from said centering means and engaging said coil spring to lock said coil spring in position.

5. A lampholder for an electric lamp comprising a split housing formed of insulating material with front and rear vertical walls in perpendicular relationship to side walls, said split housing including a pair of housng sections joined to form said side walls of said split housing, one of said housing sections having a ribbed projection extending from one of said vertical walls into the other of said housing sections in interlocking relation therewith, at least one resilient contact strip disposed in edgewise relation between the vertical wall of said other housing section and said ribbed projection, said strip being formed with a first and second contact portion, and said projection including means for locking said resilient contact strip in said other housing section, means including said first contact portion for establishing an electrical connection with the electric lamp, and means for connecting the second contact portion of the contact strip in circuit with at least one conductor lead.

6. A lampholder for an electric lamp comprising a housing formed of insulating material with front and rear vertical walls in perpendicular relationship to side walls, said housing including a pair of housing sections joined to form said side walls of said housing, one of said housing sections having a projection extending from one of said vertical walls into the other of said housing sections, a resilient contact strip disposed in edgewise relation between a vertical wall of said other housing section and, said projection, said projection including means in engagement with an edge of said resilient contact strip for locking said resilient contact strip in said other housing section, said resilient contact strip including a spring contact portion, means for connecting one end of said resilient contact strip with a conductor lead, said housing sections having a plunger-receiving opening formed therein, said opening in at least one of said housing sections having a pair of opposed axially extending ribs formed therein, a plunger slidably mounted in said plunger-receiving opening, said plunger having opposed slots engaging said ribs formed in said plunger-receiving opening, a current-carrying coil spring having one end engaging said plunger for normally biasing said plunger outwardly from said housing, the other end of said coil spring engaging said contact portion of said contact strip, means at said one end of said coil spring for providing an electrical connection with the electric lamp, and flange means on said plunger engageable with one of said housing sections for limiting the outward movement of said plunger.

References Cited by the Examiner UNITED STATES PATENTS 2,446,154 7/1948 Haven 339-55 2,722,666 11/1955 Hodgkins 33955 2,883,639 4/1959 Kulk'a 339-56 X 2,977,563 3/1961 Lennox 339-31 3,005,175 10/1961 Pistey 33950 3,060,399 10/1962 Pistey 33953 EDWARD C. ALLEN, Primary Examiner. J QSEPH D. SEERS, ALFRED S. TRASK, Examiners, 

5. A LAMPHOLDER FOR AN ELECTRIC LAMP COMPRISING A SPLIT HOUSING FORMED OF INSULATING MATERIAL WITH FRONT AND REAR VERTICAL WALLS IN PERPENDICULAR RELATIONSHIP TO SIDE WALLS, SAID SPLIT HOUSING INCLUDING A PAIR OF HOUSING SECTIONS JOINED TO FORM SAID SIDE WALLS OF SAID SPLIT HOUSING, ONE OF SAID HOUSING SECTIONS HAVING A RIBBED PROJECTION EXTENDING FROM ONE OF SAID VERTICAL WALLS INTO THE OTHER OF SAID HOUSING SECTIONS IN INTERLOCKING RELATION THEREWITH AT LEAST ONE RESILIENT CONTACT STRIP DISPOSED IN EDGEWISE RELATION BETWEEN THE VERTICAL WALL OF SAID OTHER HOUSING SECTION AND SAID RIBBED PROJECTION, SAID STRIP BEING FORMED WITH A FIRST AND SECOND CONTACT PORTIUON, AND SAID PROJECTION INCLUDING MEANS FOR LOCKING SAID RESILIENT CONTACT STRIP IN SAID OTHER HOUSING SECTION, MEANS INCLUDING SAID FIRST CONTACT PORTION FOR ESTABLISHING AN ELECTRICAL CONNECTION WITH THE ELECTRIC LAMP, AND MEANS FOR CONNECTING THE SECOND CONTACT PORTION OF THE CONTACT STRIP IN CIRCUIT WITH AT LEAST ONE CONDUCTOR LEAD. 